Case IH 518150-00 - BCM – Body Control Module (BCM): Electrical crank power relay - too many loads or faulty load

The control module is detecting an excessive current draw, incorrect resistance, or a short circuit on the circuit that controls the starter/crank relay. This happens when the circuit is subjected to more electrical demand than it is rated for, which can be caused by a short to ground, a failed relay coil, or unauthorized aftermarket accessories spliced into the circuit.

• MAGNUM AFS Connect

1. 1

   Verify battery voltage and ensure connections are clean, as low voltage can cause erratic BCM behavior

2. 2

   Inspect the Run/Crank Power Relay and its socket terminals for signs of melting, corrosion, or arcing

3. 3

   Test the resistance of the relay control circuit using a multimeter to check for a faulty load

4. 4

   Check the wiring between the BCM and the crank power relay for a short to ground or a short to battery

5. 5

   Verify that no external accessories (like aftermarket lights or monitors) have been improperly spliced into the crank relay circuit

1. 1

   Disconnect Power

   Disconnect the negative battery cable before performing electrical repairs.

2. 2

   Replace the Relay

   If the run/crank power relay fails a bench test (e.g., the coil is shorted internally, causing the excessive load), replace the relay.

3. 3

   Repair Wiring

   If a short to ground is found in the harness between the BCM and the relay block, locate the chafed wire and repair it using OEM-approved splicing methods.

4. 4

   Remove Unauthorized Loads

   If aftermarket equipment is tapped into the BCM crank circuit, remove it and route it to a dedicated fused power source.

5. 5

   Clear Codes

   Reconnect the battery, turn the ignition on, and use a diagnostic scan tool to clear the BCM fault codes. Test the cranking circuit to ensure the code does not return.